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參數(shù)資料
| 型號： | 73K302L |
| 廠商： | TDK Corporation |
| 英文描述： | Single-Chip Modem |
| 中文描述： | 單芯片調(diào)制解調(diào)器 |
| 文件頁數(shù)： | 24/29頁 |
| 文件大?。?/td> | 282K |
| 代理商： | 73K302L |
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73K302L
Bell 212A, 103, 202
Single-Chip Modem
24
RXA
-
+
R4
37.4K 1%
C1
390 pF
TXA
C10
0.47 μF
250V
D1
IN4004
R12
22K
T1
MIDCOM
671-8005
VR1
MOV
V250L20
T
R
U2
4N35
U1C
*
R2
20K 1%
C6
0.1 μF
+5V
+
-
U1B
*
+5V
K1
D4
IN914
2N2222A
Q1
R14
10K
10
9
8
R1
20K 1%
R3
475 1%
7
6
5
4
11
R5 3.3K
C4
0.0047 μF
R6
22.1K
R7
20K 1%
C3
0.1 μF
C5
750 pF
R9
20K 1%
R8
20K 1%
-
+
U1A
*
1
3
2
C2
0.033 μF
3.3V
ZENERS
D2
D3
+5V
R13
22K
+5V
C7
0.1 μF
C8
10 μF
HOOK
RING
VOLTAGE
REFERENCE
R10
*
R11
*
+
APPLICATIONS INFORMATION
(continued)
DIRECT ACCESS ARRANGEMENT (DAA)
The telephone line interfaces show two examples of
how the “hybrid” may be implemented. The split
supply design (Figure 1) is a typical two op-amp
hybrid. The receive op-amp serves two purposes. It
supplies gain to amplify the receive signal to the
proper level for the modem’s detectors and
demodulator, and it removes the transmitted signal
from the receive signal present at the transformer.
This is done by supplying a portion of the
transmitted signal to the non-inverting input of the
receive op-amp at the same amplitude as the signal
appearing at the transformer, making the transmit
signal common mode.
The single-supply hybrid is more complex than the
dual-supply version described above, but its use
eliminates the need for a second power supply. This
circuit (Figure 2) uses a bridged drive to allow
undistorted signals to be sent with a single 5V
supply. Because DTMF tones utilize a higher
amplitude than data, these signals will clip if a
single-ended drive approach is used. The bridged
driver uses an extra op-amp (U1A) to invert the
signal coming from the gain setting op-amp (U1B)
before sending it to the other leg of the transformer.
Each op-amp then supplies half the drive signal to
the transformer. The receive amplifier (U1C) picks
off its signal at the junction of the impedance
matching resistor and the transformer. Because the
bottom leg of the transformer is being driven in one
direction by U1A and the resistor is driven in the
opposite direction at the same time by U1B, the
junction of the transformer and resistor remains
relatively constant and the receive signal is
unaffected.
DESIGN CONSIDERATIONS
TDK Semiconductor's 1-chip modem products
include all basic modem functions. This makes these
devices adaptable for use in a variety of
applications, and as easy to control as conventional
digital bus peripherals.
FIGURE 2: Single 5V Hybrid Version
Note: Op-amp U1
must be rated for
single 5V operation.
R10 & R11 values
depend on Op-amp
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| 73K302L-IH | Single-Chip Modem |
| 73K302L-IP | Single-Chip Modem |
| 74ALVCH2245 | Low Voltage Bidirectional Transceiver with Bushold and 26з Series Resistors in B Outputs |
| 74ALVCH2245MTC | 3-Line To 8-Line Decoders/Demultiplexers 16-SOIC -40 to 85 |
| 74ALVCH2245WM | 3-Line To 8-Line Decoders/Demultiplexers 16-SOIC -40 to 85 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| 73K302L-IH | 制造商:TDK 制造商全稱:TDK Electronics 功能描述:Single-Chip Modem |
| 73K302L-IP | 制造商:TDK 制造商全稱:TDK Electronics 功能描述:Single-Chip Modem |
| 73K321L | 制造商:TDK 制造商全稱:TDK Electronics 功能描述:CCITT V.23, V.21 Single-Chip Modem |
| 73K321L-IH | 制造商:TDK 制造商全稱:TDK Electronics 功能描述:CCITT V.23, V.21 Single-Chip Modem |
| 73K321L-IP | 制造商:TDK 制造商全稱:TDK Electronics 功能描述:CCITT V.23, V.21 Single-Chip Modem |
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